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The Mote Marine Laboratory released at the end of March the first hatchery-raised Caribbean king crabs on a coral reef in the Lower Florida Keys, marking a historic milestone for the restoration of Florida's coral reef system, the third largest in the world, reported WFLA-TV.
The Florida coral reef has lost over 90% of its living coral in the last 75 years due to overfishing, diseases, algal blooms, and climate stress, and the project aims to reverse that collapse through a strategy that goes beyond simple coral transplantation.
The release took place at the Florida Coral Reef Restoration Crab Hatchery Research Center, a pioneering 6,000 square foot facility located in the Aquaculture Research Park at Mote in Sarasota, which currently houses over 300 adult crabs and has the capacity to produce up to 250,000 juveniles per year.
The Caribbean king crab (Maguimithrax spinosissimus) is regarded as one of the most effective herbivores in the western Atlantic: it consumes macroalgae that block sunlight and compete with young corals for space, including species that other herbivores avoid, such as Amphiroa, Halimeda, and Dictyota.
Previous studies show that their presence can reduce algal coverage by 50% to 85%, significantly increasing coral recruitment and the abundance of reef fish.
Dr. Jason Spadaro, manager of Mote's coral reef restoration program, described the behavior of the animals after their release: "As we released the crabs into the reef, almost all of them immediately grasped a piece of algae, put it in their mouths, and ran to take shelter," reported Fox News.
Juveniles take between three to five months to reach the appropriate size for their release, after undergoing veterinary examination, and the first successful birth in captivity occurred in February 2022.
The ultimate goal of the project is to release 35,000 crabs along the Florida Keys National Marine Sanctuary, from Key Largo to the west of Key West, with additional releases planned for this April.
The urgency of the project is evident given the scale of the accumulated damage: the marine heatwave of 2023 was the worst recorded in Florida's history, with sea surface temperatures reaching up to 38°C in the Florida Keys, causing 100% bleaching at sites such as Horseshoe Reef, Cheeca Rocks, Sombrero Reef, and Looe Key, according to CBS News.
After that catastrophe, two critical species —staghorn coral and elkhorn coral— were declared functionally extinct in the region by the University of Miami in October 2025.
This is coupled with the tissue loss disease in stony corals, first detected in September 2014 near Miami, which has affected more than 90% of the susceptible corals in the region.
Mote has been conducting coral transplants since 2008, and 75% of the corals planted during that period survived the recent heatwave and continue to grow and reproduce.
Dr. Spadaro summarized the philosophy that guides the effort: "Now is not the time to give up; now is the time to intensify the work."
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